1. Field of the Invention
The present invention relates to a valve device for controlling the flow of a fluid, so that the fluid can flow in a particular direction. More particularly, the present invention relates to a valve device for a fluid, such as molten metals, that may be used to control the flow of molten metal usually heated at high temperatures such as 1000 C. degrees or more, so that the fluid can flow in a particular direction.
2. Description of the Prior Art
Conventionally, as means for controlling the flow of molten metal usually heated at 1000 C. degrees or more so that the molten metal can flow in a particular direction, the valve device such as the one shown in FIG. 9 is employed. As shown, this valve device includes a fluid pipe 17 equipped with a sealing 20 on one lateral side thereof, and a valve body 19 that is fitted into the fluid pipe 17 on the lateral side so that it can be moved into or away from the fluid pipe 17 transversely thereof. By moving the valve body 19 into or away from the fluid pipe 17 transversely thereof in the direction of a double arrow 21, the valve device is operated so that the flow of the molten metal coming through the fluid pipe 17 in the direction of an arrow 22 may be controlled so that the molten metal can flow toward the fluid pipe 18 as indicated by an arrow 23 and then in the direction of arrows 24a, 24b, for example.
According to the prior art valve device described above, the valve body makes a sliding contact or pressure contact against the internal wall of the fluid pipe, thereby sandwiching molten metal between the valve body and the internal walls of the fluid pipe. Thus, any impurities present in the molten metal may damage the surface of the valve body upon making the sliding or pressure contact against the internal walls of the fluid pipe, and may affect the anticorrosiveness or durability of the valve body.
Also, according to the prior art valve device, when the flow of the molten metal is suspended and remains motionless, the molten metal becomes solidified, which may the attach to the valve body and other parts. This may make the valve device inoperative so that it is difficult to restart the valve device.
In transporting the molten metal from a blast furnace, holding furnace or the like to a particular destination, it is desired to develop a valve device that can control the flow of molten metal accurately and reliably so that the flow can occur in a particular direction, and that can save the labor and time required to remove any attached solidified metal, at the time when the valve device is to be restarted after the transport of the molten metal flow is suspended.